Dry process of manufacturing Portland cement

 There are two process of manufacturing cement - 1) Dry process and 2) Wet process.

  In dry process, water is not mixed with raw materials during manufacturing process while in wet process, mixing of water takes place while manufacturing.

  The raw materials used for manufacture of Portland cement are calcareous materials like lime stone and argillaceous materials like clay.

Dry process of cement includes following steps :-

• The raw materials are first reduced in size of about 25 mm in crushers.
• A current of dry air is then passed over these dried materials.
• These materials are then pulverized into fine powder in ball mills and tube mills. 
• All of the above operations are done separately for each raw material and they are stored in hoppers.
• They are then mixed in correct proportions and burned in a rotary kiln at a temperature of about 1300 - 1500 degree celsius.
• In the kiln, the materials sinter and then they gets fused to form nodular shaped clinker. 
• The clinker is cooled and ground to a fine powder with addition of about 2-3% of gypsum.
• The product formed is Portland cement.

 Dry process of manufacturing cement is the modern process. In this process, operation time of rotary kiln is less and thus fuel consumption gets reduced. This is cheap than wet process and eco-friendly too.

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